Treating artificial silk



Patented Nov. 20, 1928.

UNITED STATES PATENT orrica TREATING ARTIFICIAL SILK.

No Drawing.

This invention relates to a method of delusterizing and otherwiseimproving the chara'cter'of textile fibers, threads, films, or fabrics,known as artificial silk, such as are produced from nitrocellulose,cupro-ammonium cellulose, cellulose acet ate, cellulose Xanthate(viscose), cellulose others and similar cellulosic starting materials,and to the resulting products.

Artificial silk products usually have a very high luster and atransparency which gives them an appearance unlike the more pleasingappearance of natural silk.

I have found that the character of artificial silk products may beimproved by impregnating the same with an aqueous solution of a salt oftitanium, and subsequently decomposing the salt in situ. Thus there isprecipi: tated in or commingled throughout the fibers of the artificialsilk 2. hydrated oxide or other insoluble compound of titanium which iswhite and very opaque, giving to the artificial silk a delusterized'appearance, and producing such light absorption eif'ects as aredesirable,

As an example, the following is given. 4 grams of a water-soluble saltof titanium, such as for instance, titanium sulphate or an equivalentamount of titanium potassium OX- alate or other suitable salts oftitanium, are dissolved in 1000 grams of water. 100 grams of artificialsilk are immersed in this solution and allowed to remain there untilthorough impregnation iscfiected, and the solution is then heated to atemperature of from about 65 to about 100 C. Or, the artificial silkimpregnated with the titanium salt solution is heated injan autoclave todecomposethe titanium salt.

After the decomposition treatment, the artificial silk is washed toremove any soluble matter. and then dried.

The'finished product, instead of having the very high luster ofartificial silk, has a pleasing, semi-delusterized appearance. Insteadof having the transparent appearance of ordinary artificial silk, itriswhite, and has an opacity which immediately distinguishes it. Thisopacity is due to the absorption of light by the precipitated titaniumcompound. The product, moreover, may be dyed readily. Although theinvention has been described by reference to the treatment of artificialsilk with a solution of a salt of titanium of a specific strength,- itis to'be understood that Application filed May 13,

1927. Serial No. 191 276.

the inventive concept includes the treatment of artificial silk with asolution of said salt of any suitable strength. In-general', however,the use of fairly dilute solutions is desirable. Furthermore, it is tobe understood that the invention does not reside in the use of anyspecific solvent.

Onlya small amount of deposited insoluble titanium compound is requiredto give the effects described. Thus for'insta-nce, artificial silksotreated'that therewill be present.

as low as 0.5% of titanium oxide will be delusterized. r I i I claim:, II

1. Process ofdelusteriizing artificial silk fibers whichcomprisesimpregnating the same with a dilute aqueous solution of atitanium salt which is thermally decomposable in the presence ofwat'er,and. heating the impregnated fibers in the presence of waterwhereby there is deposited in, and upon the fibers a water-insolubletitanium compound, the concent-ration of the titanium salt solution usedbeing such as to increase the weight of the so-treated artificialsilkfiber's from about4% to about 0.5%. v

2,. Process of delustcrizing artificial silk fibers which comprisesimpregnating about 100part-s by weight of said fibers with a diluteaqueous solution containing not more salt of titanium which is thermallydecomposable in the presence of water, and heating the impregnatedfibers to a temperature of from about 65 to about 100 (3., in the presence of water.

3. Process of delusterizing artificial silk fibers which comprisesimpregnating about 100 parts by weight of said fibers with a diluteaqueoussolntion containing not more than about 4 parts by weight ofwater-soluble than about 4 parts by weight of titanium sulfate, andheating the impregnated fibers to a temperature of from about 65 toabout C. in the presence of'water.

4. As a new product, delusterized artificial silk fibers containing afinely divided, Waterinsoluble titanium compound in amount not. greaterthan about'4% by weight.

5. As a new product, delusterized artificial silk fibers containing afinely divided hydrated oxide of titanium in amount no greater thanabout 4% by weight.

In testimony whereof, I afiix my signature.

" HENRY acaanuna.

